Introduced SimpleTransactionScope (analogous to SimpleThreadScope)

Issue: SPR-13085

spring-tx/src/main/java/org/springframework/transaction/support/SimpleTransactionScope.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.transaction.support;
+
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.beans.factory.ObjectFactory;
+import org.springframework.beans.factory.config.Scope;
+
+/**
+ * A simple transaction-backed {@link Scope} implementation, delegating to
+ * {@link TransactionSynchronizationManager}'s resource binding mechanism.
+ *
+ * <p><b>NOTE:</b> Like {@link org.springframework.context.support.SimpleThreadScope},
+ * this transaction scope is not registered by default in common contexts. Instead,
+ * you need to explicitly assign it to a scope key in your setup, either through
+ * {@link org.springframework.beans.factory.config.ConfigurableBeanFactory#registerScope}
+ * or through a {@link org.springframework.beans.factory.config.CustomScopeConfigurer} bean.
+ *
+ * @author Juergen Hoeller
+ * @since 4.2
+ * @see org.springframework.context.support.SimpleThreadScope
+ * @see org.springframework.beans.factory.config.ConfigurableBeanFactory#registerScope
+ * @see org.springframework.beans.factory.config.CustomScopeConfigurer
+ */
+public class SimpleTransactionScope implements Scope {
+
+	@Override
+	public Object get(String name, ObjectFactory<?> objectFactory) {
+		ScopedObjectsHolder scopedObjects = (ScopedObjectsHolder) TransactionSynchronizationManager.getResource(this);
+		if (scopedObjects == null) {
+			scopedObjects = new ScopedObjectsHolder();
+			TransactionSynchronizationManager.registerSynchronization(new CleanupSynchronization());
+			TransactionSynchronizationManager.bindResource(this, scopedObjects);
+		}
+		Object scopedObject = scopedObjects.scopedInstances.get(name);
+		if (scopedObject == null) {
+			scopedObject = objectFactory.getObject();
+			scopedObjects.scopedInstances.put(name, scopedObject);
+		}
+		return scopedObject;
+	}
+
+	@Override
+	public Object remove(String name) {
+		ScopedObjectsHolder scopedObjects = (ScopedObjectsHolder) TransactionSynchronizationManager.getResource(this);
+		if (scopedObjects != null) {
+			scopedObjects.destructionCallbacks.remove(name);
+			return scopedObjects.scopedInstances.remove(name);
+		}
+		else {
+			return null;
+		}
+	}
+
+	@Override
+	public void registerDestructionCallback(String name, Runnable callback) {
+		ScopedObjectsHolder scopedObjects = (ScopedObjectsHolder) TransactionSynchronizationManager.getResource(this);
+		if (scopedObjects != null) {
+			scopedObjects.destructionCallbacks.put(name, callback);
+		}
+	}
+
+	@Override
+	public Object resolveContextualObject(String key) {
+		return null;
+	}
+
+	@Override
+	public String getConversationId() {
+		return TransactionSynchronizationManager.getCurrentTransactionName();
+	}
+
+
+	static class ScopedObjectsHolder {
+
+		final Map<String, Object> scopedInstances = new HashMap<String, Object>();
+
+		final Map<String, Runnable> destructionCallbacks = new LinkedHashMap<String, Runnable>();
+	}
+
+
+	private class CleanupSynchronization extends TransactionSynchronizationAdapter {
+
+		@Override
+		public void afterCompletion(int status) {
+			ScopedObjectsHolder scopedObjects = (ScopedObjectsHolder)
+					TransactionSynchronizationManager.unbindResourceIfPossible(SimpleTransactionScope.this);
+			for (Runnable callback : scopedObjects.destructionCallbacks.values()) {
+				callback.run();
+			}
+		}
+	}
+
+}